This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The overall goal of the project is to develop a statistical multi-modal population brain atlas construction framework incorporating all the available imaging modalities. The imaging modalities that the framework will support are T1, T2, various diffusion weighted protocols such as DWI and DSI as well as arterial spin labeling perfusion MRI. The atlas construction framework will be used to study the anatomy of the aging brain and impact of various diseases on the aging process. In particular, the generation of probabilistic brain atlases will improve power to identify systematic brain differences between diseases and aging brains by utilizing information of local brain variability. Moreover, a probabilistic brain atlas that includes jointly information from all imaging modalities will allow more comprehensive investigations in brain alterations than conventional methods that use a single image modality or multiple modalities separately. Moreover, the mapping of multimodal image data into a common 3D coordinate space is a prerequisite for many imaging analysis projects of this P41, as it supplies a quantitative spatial reference system in which brain data from multiple subjects and modalities can be compared and correlated.